// This tests mutually recursive function definitions.

bool even(int n) {
  cond {
    n == 0 => return true;
    n < 0  => return even(-n);
    else      return odd(n - 1);
  }; 
}

// If the following line is uncommented, loading this file
// should fail because even and odd are no longer considered
// mutually recursive.
//
// _ = null;

bool odd(int n) {
  cond {
    n == 0 => return false;
    n < 0  => return odd(-n);
    else      return even(n - 1);
  }; 
}